In the United States and in many other countries of the world today, large flat sheets of standardized length and width are commonly employed. As an example, for frame construction buildings, that is buildings built from wherein the super structure is primarily of wood, typically employing wood rafters, the roof is formed by first laying down on the exposed spaced apart rafters a sheeting of plywood or particle board. In the United States a typical size plywood sheet used for roofing is 4 feet by 8 feet with a thickness of typically 3/8 inches to 3/4 inches. If a roof has a valley or a hip it means that some of the 4.times.8 foot sheets must be cut at an angle at one end to fit the adjoining hip roof or valley. The angle of cut required is determined by the pitch of the roof or the pitch of the hip which the roof intersects. As subsequent rows of building material sheets are attached to a rafter superstructure, sheets are required to complete a row having the same angular cut although the length of the sheet from the angular cut to a square end will vary for each row.
Typically, in installing sheeting on rafters installers on the roof will measure to determine the length of one edge of a 4.times.8 foot sheet. A workman can then calculate from existing tables the length of the other edge. A straight line is drawn between the markings on the two edges and the sheating is cut along the straight line so that when in position it will match a hip or valley of the roof.
The same procedure is employed when sheets of standardized building material sheets, such as 4.times.8 foot sheets are installed vertically on the side of a building. If the building has a gable roof, the vertical sheeting must match the angle of the roof as various sheets are employed the same angle cut is required at the point where the sheeting meets the gabled roof. While tables exist that provide the length differential of the parallel side edges of the 4.times.8 foot sheets to match valley, hips and gable usages it is time consuming to use tables for marking individual sheets in the construction of the roof or gable since particularly for each roof or gable is the same angular relationship existing from the start to the completion of the roof. It is an object of the present invention to provide a tool for use in marking large flat building material sheets in which each sheet has a standardized length and a standardized width and has opposed longitudinal edges to provide dimensional shapes for a series of sheets for completing a roof or a gable.
For background information relating to tools of different kinds used by construction craftsman for providing measurement relationships, reference may be had to the following previously issued U.S. patents:
U.S. Pat. No. INVENTOR TITLE 372,673 Hamilton, Jr. Lumber Rule 575,671 Watts et al. Telescopic Measuring Rule 753,886 Jacobs Ruler 792,212 Heddle Protractor Gage 825,150 McCartney Attachment for Carpenters' Squares 833,168 Keller Scale Guard and Marker 1,056,206 Norman Rafter Reckoner 1,074,969 Moore Combined Level and Square 1,084,973 Stanwood et al. Try, Rafter, and Miter Square 2,763,065 Leidahl Marking Gage for Rules 3,015,163 Cummings Square Attachment 3,934,350 Pirnie Photo Cropping Device 4,462,166 Furlong Device for Measuring Lengths and Conforming Angles 4,648,185 Brandimarte Leveling Tool